Polyvinyl acetal resin sheets containing triethylene glycol diacetate



Patented Dec. 26 1939 POLYVINYL ACETAL RESIN SHEETS CON- TAININGTRIETHYLENE GLYCOL DIAGE-' TATE Henry B. Smith, Rochester, N. Y.,assignor to Eastman Kodak Company, Rochester, N. Y. a corporation of NewJersey No Drawing.

2 Claims.

This invention relates to plastic compositions, and more particularly tocompositions comprising a polyvinyl acetal resin. and a conditioningagent.

One object of this invention is to produce compositions of matter whichmay be made into permanently transparent, strong and flexible sheets orfilms of desired thinness which are substantially waterproof, areunafiected by ordinary photographic fluids and possess the desiredproperties of a support for sensitive photographic coatings. Anotherobject of my invention is to produce compositions of matter which can bemade into sheets suitable for use in laminated, shatterproof glass.Still another object is to produce compositions which can -be rolled,extruded, molded or otherwise worked into relatively thick sheets andmassive plastics. A further object is to produce compositions suitablefor use in lacquers, artificial silk filaments, wrapping tissues and thelike. Other objects will hereinafter appear. v

I have discovered that thiethylene glycol diacetate is a usefulconditioning agent for polyvinyl acetal resins. Not only does itserve asa plasticizer in the accepted sense of the term, increasing theflexibility and toughness of polyvinyl acetal resin films, sheets; orother objects or masses containing it, but when used in-amounts of about40 or 'more parts per 'parts of the resin, it has an unusual andremarkable effect which I may call elasticizing.- ,That is'to-say, asheet of polyvinyl acetal resin containing about 40 or more parts oftriethylene glycol diacetate per 100 parts of resin possesses theproperty which; in fthe rubber; industry, is known as nerve: namely, theproperty of stretching to a considerable extent when ,tension is exertedupon it, and returning to its original dimensions when the tension isreleased, This propertyrenders such sheets, which'I; shall call'-rubberyl sheets,

proof glass.

,particularlyuseful; in the manufacture of shatter- I For themanufacture oi; or sheets, the

polyvinyl acetal -resin;.-an'd, triethylene glycol-die acetate may bedissolvedin a suitable solvent". or solvent mixture suoh,-;.foriinstance, as acetone, methanol, (acetone-methanol amixtures ,1.ethylene chloride-methanol;- mixtures, etc-.; j about- 2 300;; to 500+or mole parts I of-the solvent or {solvent mile ture beingused per 100,parts-oi. the resin. J From aboutLS to 100' parts or more .oftriethylene glycol diacetate per 100. parts of resin may be-employed,

dependinguponthe nature of thefresi'n and% the purpose ,for whichtheslieet 'SISQIQIJPG Application February 1,1938, Serial No. 188,195

Suitable proportions of triethylene glycol diacetate for any resin andany purpose may be readily determined by experiment. For the manufactureofsheets suitable for photographic film base. from 13 to 25 parts oftriethylene glycol diacetate per 100 parts of resin are suitable. Theresin solution is cast as a sheet, the solvent evaporated, and the sheetstripped from the casting surface.

Sheets for use in laminated glass may be formed by casting, or may bemade without the use of volatile solvent by extrusion, for example inthe manner set forth in application Serial No. 147,934 of John S. Kimbleand Ernest C. Blackard, filed June 12, 1937. For instance, 40 or moreparts of triethylene glycol diacetate and 100 parts mass. thus producedmay then be extruded through an annular die, and the tube so formed slitto form a sheet. When the resin used is a polyvinyl formaldehyde acetalresin, it will usually be found necessary to use.'75 or more parts oftriethylene glycol diacetate.

The polyvinyl acetal'resins can be prepared by reacting polyvinylalcohol with .an aldehyde 1n the presenbeof an acetal condensationcatalyst,

.e. g. a mineral acid. These resins can also be prepared bysimultaneously de-esterifying'a polyvinyl aliphatic ester and reactingthe de-esterification product with an aldehyde in the presence of ade-esterifying catalyst and acetal condensation catalyst.

Among the polyvinyl'acetal resins with which tri ethylene glycoldiacetate is useful may be meng tioned, as illustrative. examples, .thepolyvinyl formaldehyde acetal resins, the polyvinyl acetal Mineralacidsarecatalysts for g both de e-esterification and acetal formation.

dehyde acetal resins, the polyvinyl formaldehyde acetaldehydefm'xed'agietn resins, the-' polyvll lljl butyralde'l'iyde' "acetal resins; and;the polyvinyl butyraldehyd inixedj'acet'a'l resins. Examples ofthe'preparation of polyvinyl formaldehydeacetal resinsmaybe foundinU.'S'.Pat-' 3 T' whose molar solution (86.08 g. per liter) in benzeneswas 45 centipoises, was dissolved in 75 lbs. of 70% acetic acid. To thissolution were added-56 grams of hydroxylamine hydrochloride, forstabilizing the resin, 5.25 lbs. of trioxymethylene, and 6.25 lbs. of35% HCl. The reaction mixture was allowed to stand for days at 40 C.,after which it was diluted with acetic acid. The resin was .precipitatedby pouring into cold water, washed,

and dried. Analysis showed the resin to have an acetate group contentequivalent to 10.6% by weight of polyvinyl acetate and a hydroxyl groupcontent equivalent to 7.1% by weight of polyvinyl alcohol. Thestabilization of polyvinyl acetal resins by hydroxylamine is claimed inthe application of Joseph B. Hale, Serial No. 149,916, filed June 23,1937, Patent No. 2,146,735.

70 lbs. of polyvinyl acetate, the viscosity of whose molar solution inbenezene was 45 centipoises, was dissolved in a mixture of 336 lbs. of

glacial acetic acid and 224 lbs. of water. After solution was effected,there were added a solution of 318 grams of sodium nitrite in 500 cc. ofwater, for stabilizing the resin, 15.2 lbs. of trioxymethyl'e'ne'and17.5 lbs. of 35% HCl. The reaction mixture was allowed to stand for 5days at 40 C., whereupon 5 lbs. additional 35% 1101 was added and thereaction continued for 6 days longer; a total of 11 days at 40 C. Thereaction mixture was then diluted with a mixture of acetic acid andethyl alcohol, and the resin was precipitated bypouring into cold water,washed and dried.

Analysis showed the resin to have an acetate group content equivalent to10.7% by weight of polyvinyl acetate and a hydroxyl group contentequivalent to 11.2% by weight of polyvinyl alcohol. The stabilization ofpolyvinyl acetal resins by nitrous acid is claimed in the application ofCharles R. Fordyce and Martti Salo, Serial No.

-Patent 2,044,730, Example 1; U. S. Patent 1,955,068, Example 2; U. S.Patent 2,036,092, Examples 4, 5, and 6; British Patent 466,598, Examples1, 2, 3; 4, and '7; British Patent 404,279,

Examples 1, 2, 4, 5, 6, 7, and 8; U. S. Patent- 1,990,399; and FrenchPatent 808,578, Examples 1, 2, and 3.

Additional examples of the preparation of polyvinyl acetaldehyde acetalresins are as followsf 100 lbs. of polyvinyl acetate, the viscosity ofwhose molar solution in benzene was 45 centipoises, was dissolved in 300lbs. of 95% ethyl alcohol. To this solution were added lbs. ofparalydehyde and 25 lbs. HCl. The reaction mixture was allowed to standfor 4 days at C., after which it was diluted with ethyl alcohol, and theresin precipitated by pouring into cold water, washed and dried.Analysis showed the resin to have an acetate group content equivalent to2.1%

by weight of polyvinyl acetate and a hydroxyl,

, hyde and a solution of 3 lbs. 12 ozs. .of sulfuric acid in 3 lbs. 1202s. of 95% ethyl alcohol. The

reaction mixture was allowed to stand for 7 days at 40 C., after whichit was diluted with ethylalcohol, and the resin precipitated by pouringinto cold water,-washed, and dried. Analysis showed the resin to have anacetate group content equivalent to 1.7% by weight of polyvinyl acetateand a hydroxyl group content equivalent to 13.8% by weight of polyvinylalcohol.

, Examples of the preparation of polyvinyl formaldehyde acetaldehydemixed acetal resins may be found in British Patent 430,136, Examples 1,2, 3', 4, 5, and 6; British Patent 445,565, Example 2; British Patent465,873, Examples 1, 2, 3, 4, 5, and 6; French Patent 808,586, Examples1,2, 3, 4, 5, 6, 12, 13, 14, 15, 16, 17, 18, and 19.

Additional examples of the preparation of polyvinyl formaldehydeacetaldehyde mixed acetal resins are given in the application of RalphH. Talbot, Serial No. 85,960, filed June 18, 1936, as follows:

Example 1 100 parts (1.16 mol. calculated as monomeric vinyl acetate) ofa polyvinyl acetate centipoises), 100 parts of ethyl alcohol, 180 partsof ethyl acetate, 34 parts (.77 mol. as monomeric acetaldehyde) ofparacetaldehyde and 5.8 parts (.196 mol. as monomeric formaldehyde) ofparaformaldehyde were placed in an enamelled vessel and brought intosolution by stirring. When solution was complete, 10 parts of sulfuricacid (sp. g. 1.84) in 10 parts of water were added, and the mixturevstirred. The mixture was maintained at a temperature of 40C. for 144hours. The contents of the vessel were then diluted with about two and ahalf volumes of acetone, and the mixture precipitated into water. Theprecipitated resin was washed free from impurities by repeated changesof cold water, and dried. The resin, when analyzed, gave a hydroxylgroup content equivalent to about 6.4. per cent by weight of polyvinylalcohol, an acetate group content equivalent to about 4.0 per cent byweight of polyvinyl acetate, a formaldehyde acetal group contentequivalent to about 15.9 per cent by weight of polyvinyl formaldehydeacetal and an acetaldehyde acetal group content equivalent to about 73.9per cent by weight of polyvinyl acetaldehyde acetal. The polyvinylacetal portion of the resin was therefore made up of about 19.7 percentby moles of polyvinyl formaldehyde acetal and about 80.3 per cent bymoles of polyvinyl acetaldehyde acetal. The resin was soluble'in acetoneto an extent which permitted coating afllm or sheet from the resin.

Example 2 parts (.58 mol. as monomer) of polyvinyl acetate (45cntipoises), 50 parts of ethyl alcohol, 90 parts of ethyl acetate, 17parts (.385 mol. as monomer) of paracetaldehyde, 2.9 parts (.098 mol. asmonomer) of paraformaldehyde, 5 parts of sulfuric acid and 5 parts ofwater were treated. as in Example 1 for 161 hours. The well washed anddried resin gave upon analysis a hydroxyl group content equivalent toabout 9.6% by weight of polyvinyl alcohol, an acetate group contentequivalent to about 4.1% by weight of polyvinyl acetate, a formaldehydeacetal group con-tent equivalent to about 13.9 percent by weight ofpolyvinyl formaldehyde acetal, and an acetaldehyde acetal group contentequivalent to about ,69.9 per vcent of polyvinyl acetaldehyde acetal.The polyvinyl acetal portion of the resin was therefore made up of about18.5 per Example 3 1300 parts (15.1 mol. as monomer) of apolyvinyLacetate centipoises), 1700 parts of ethyl acetate, 2250 partsof ethyl alcohol (95%) and 48 parts (1.57 mol. as monomer) ofparaformaldehyde (trioxymethylene) were placed in a vessel equipped witha reflux condenser and a means of agitation, and the contents brought toa temperature of about C. by means of steam heating. 182.25 parts ofsulfuric acid (sp. g. 1.84) dissolved in 51.5 parts of water were added,and the whole was heated at about 70 C. for about five hours, agitatingthroughout. At this point, 266.4 parts (6.05 mol. as monomer) ofparacetaldehyde were added and heating at about 70 C. with agitation wascontinued for a further period of twenty hours. The contents of thereaction vessel were neutralized with ammonium hydroxide and 1 dilutedwith water precipitating the resin as a cake. The cake was cut intosmall pieces arid repeatedly washed with hot water until the resin wasfree from solvents, salts and other impurities? The resin, uponanalysis, showed a hydroxyl group content equivalent to about 10.1 percent by weight of polyvinyl alcohol, an acetate -group con-' tentequivalent to about 3.2 per cent by weight of by admixing small amountsof other solvents,

aldehyde acetal resins may be found in U. S. Patent 2,044,730, Examples2,5 and 6; British Patent 466,598, Example 5; French Patent 813,303,Example 1; French Patent 813,514, Examples 1, 2, 3 and 4; and BritishPatent 459,878, Examples 1, 2, 5, 6, 7, 8, 9 and 10.

An additional example of the preparation of a polyvinyl butyraldehydeacetal resin is as fol- 10 s:'

23.6 lbs. of polyvinyl acetate, the viscosity of i whose molar solutionin benzene was 45 centipoises, was dissolved in 56.5 lbs. of ethylalcohol. To this solution was added 7.9 lbs. of butyraldehyde and 5.9lbs. of 35% HCl-. The reactlon mixture was allowed to stand for 4 daysat 40 C., after which it is diluted with ethyl alcohol and acetic acid,and the resin precipitated by vinyl acetate and a hydroxyl group contentequivalent to 16.3% by weight of polyvinyl alcohol.

An example of the preparation of a polyvinyl butyraldehyde acetaldehydemixed acetal resin to impart to the sheet a rubbery character without3.3

substantially, impairing itstransparency. HENRY B. SMITH.

CERTIFICATE OF CORRECTION. Patent No. 2,18h,hh5s v December 26 1959.

I HENRY B. SMITH. It is hereby certified that error appears in theprinted specification of the above numbered patent requiring correctionas follows: Page 1, first column, line 25, for "thiethylene'! readtriethylene; and second column,

line L5, after "butyraldehyde" insert acetaldehyde; page2,-first-coli1mn, line 19, for "benezene" read benzene; and that thesaid Letters Patent should be read with this correction therein that thesame may conform to the record of the case in the Patent Office. I

Signed and sealed this 2nd day of April, A'. D. 19LLO.

Henry Van Arsdale, (Seal) Acting Coinrnis-sioner of Patents.

